U.S. patent number 6,206,520 [Application Number 09/275,866] was granted by the patent office on 2001-03-27 for contact lenses with contoured edges.
This patent grant is currently assigned to Johnson & Johnson Vision Care, Inc.. Invention is credited to Timothy Clutterbuck, Philippe Jubin, Jeffery Roffman.
United States Patent |
6,206,520 |
Jubin , et al. |
March 27, 2001 |
Contact lenses with contoured edges
Abstract
The invention provides contact lenses that have contoured lens
edges that improve lens handling and comfort.
Inventors: |
Jubin; Philippe (Jacksonville,
FL), Clutterbuck; Timothy (Jacksonville, FL), Roffman;
Jeffery (Jacksonville, FL) |
Assignee: |
Johnson & Johnson Vision Care,
Inc. (Jacksonville, FL)
|
Family
ID: |
23054150 |
Appl.
No.: |
09/275,866 |
Filed: |
March 25, 1999 |
Current U.S.
Class: |
351/159.02 |
Current CPC
Class: |
G02C
7/04 (20130101) |
Current International
Class: |
G02C
7/04 (20060101); G02C 007/04 () |
Field of
Search: |
;351/16R,16H,161,162,177 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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|
|
|
|
|
|
0 742 462 |
|
Nov 1996 |
|
EP |
|
WO 97/34185 |
|
Sep 1997 |
|
WO |
|
WO 98/00749 |
|
Jan 1998 |
|
WO |
|
Primary Examiner: Sugarman; Scott J.
Attorney, Agent or Firm: Gianneschi; Lois A.
Claims
What is claimed is:
1. A contact lens comprising a convex and a concave surface, one or
both of the surfaces consisting essentially of an optic zone and a
contoured lens edge, the contoured lens edge comprising a
functional form selected from the group consisting of a ratio of
two polynomials, a parametric function, a conic section, and
combinations thereof.
2. The lens of claim 1, wherein the convex surface consists
essentially of the optic zone and the contoured lens edge.
3. The lens of claim 1, wherein the lens is a soft contact
lens.
4. The lens of claim 2, wherein the lens is a soft contact
lens.
5. The lens of claim 1, wherein the functional form of the curve is
a ratio of two polynomials.
6. The lens of claim 1, wherein the functional form of the curve is
a parametric function.
7. The lens of claim 1, wherein the functional form of the curve is
a conic section.
8. A method for designing a contact lens comprising the steps
of:
a.) designing an optic zone for a first lens surface;
b.) selecting an x and a y coordinate for each of at least two
points on the first lens surface; and
c.) fitting a curve through the points specified in step b.) to
form a contoured lens edge, the contoured lens edge being a
substantially smooth curve comprising a functional form selected
from the group consisting of a ratio of two polynomials, a
parametric function, a conic section and combinations thereof.
9. The method of claim 8 wherein the first lens surface is the
convex lens surface.
10. The method of claim 8, wherein one of the at least two points
is at the periphery of the optic zone and one the at least two
point is at an outermost point of the lens.
11. The method of claim 9, wherein one of the at least two points
is at the periphery of the optic zone and one the at least two
point is at an outermost point of the lens.
12. The method of claim 8, wherein the functional form of the curve
is a ratio of two polynomials.
13. The method of claim 8, wherein the functional form of the curve
is a parametric function.
14. The method of claim 8, wherein the functional form of the curve
is a conic section.
15. The method of claim 11, wherein the functional form of the
curve is a ratio of two polynomials.
16. The method of claim 11, wherein the functional form of the
curve is a parametric function.
17. The method of claim 11, wherein the functional form of the
curve is a conic section.
Description
FIELD OF THE INVENTION
The invention relates to contact lenses. In particular, the
invention relates to contact lenses that have contoured edge
designs that improve lens handling and comfort.
BACKGROUND OF THE INVENTION
The use of contact lenses for cosmetics and the correction of
visual acuity is well known. Generally, the front, or convex,
surface of a contact lens incorporates an optic zone, a lenticular
zone, a bevel, and a side wall. The presence of all but the optic
zone is necessitated by the need for the contact lens to fit
comfortably, for the lens to position itself correctly on the
wearer's eye, and for the lens to be easily handled by the lens
wearer.
However, the use of the lenticular zone, bevel, and side wall is
problematic. For example, the bevel forms a junction with the
lenticular zone, which junction may act as a hinge point allowing
the bevel to turn inwardly to, or outwardly from, the wearer's eye.
Further, the junction may be sufficiently sharp so as to make the
lens uncomfortable to wear. The side wall may also cause discomfort
for the wearer. Therefore, a need exists for a lens that overcomes
some or all of these disadvantages.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a magnified, partial cross-sectional view of a lens
depicting a step in the process of the invention.
FIG. 2 is a magnified, partial cross-sectional view of a lens
depicting another step in the process of the invention.
FIG. 3 is a magnified, partial cross-sectional view of a lens
depicting another step in the process of the invention.
DETAILED DESCRIPTION OF THE INVENTION AND PREFERRED EMBODIMENTS
The invention provides contact lenses with contoured lens edges,
and methods for producing the contact lenses. The contoured lens
edges of the invention form a substantially smooth curve. By "lens
edge" is meant the area beginning at the periphery of the optic
zone and ending at the outermost point of the lens. The use of the
contoured lens edge eliminates the need for one or more of a
lenticular zone, bevel, side wall, or other zones found in a
conventional contact lens to facilitate lens handling and
orientation. Additionally, because the contoured edge forms a
smooth junction with the optic zone of the lens, the lens is more
comfortable to wear than conventional lenses. Finally, the
contoured lens edge of the invention is advantageous because it
provides greater bulk towards the lens' periphery than does a
bevel, aiding in maintaining the lens' shape and orientation and
facilitating lens handling.
In one embodiment, the invention provides a contact lens
comprising, consisting essentially of, and consisting of a convex
and a concave surface, one or both of the surfaces consisting
essentially of an optic zone and a contoured lens edge. Preferably,
the contoured lens edge of the invention is located on the convex
surface of the lens. Thus, in another embodiment, the invention
provides a contact lens comprising, consisting essentially of, and
consisting of a convex and a concave surface, the convex surface
consisting essentially of an optic zone and a contoured lens edge.
In still another embodiment, the invention provides a method for
designing a contact lens comprising, consisting essentially of, and
consisting of a.) designing an optic zone for a first lens surface;
b.) selecting an x and a y coordinate for each of at least two
points on the first lens surface; and c.) fitting a curve through
the points specified in step b.) to form a contoured lens edge, the
contoured lens edge being a substantially smooth curve having a
functional form selected from the group consisting of a polynomial,
a ratio of two polynomials, a trigonometric function, a parametric
function, a spline, a conic section, and combinations thereof.
Contact lenses useful in the invention may be either hard or soft
lenses. Soft contact lenses, made of any material suitable for
producing such lenses, preferably are used. The lenses of the
invention may have any of a variety of corrective optical
characteristics incorporated onto the surfaces. For example, the
lens may have any one or more of spheric, aspheric, bifocal,
multifocal, prismatic, or cylindric corrections. These corrections
may be on either or both the convex or concave surface. For
example, the lens of the invention may be a toric soft contact
lens, meaning that the contact has a cylindrical optical surface,
or power, to correct for the wearer's astigmatism.
In the method of the invention, the optic zone of the lens' is
designed, or its radius, diameter, shape factor, and center
thickness are determined, using any known method. Suitable methods
include, without limitation, the use of commercially available
design software. Typically, the optic zone is designed after the
base curve for the opposite surface is determined. After
determination of the base curve, the optic zone will be designed so
that the combination of the base curve and optic zone provide the
desired refractive correction for the lens.
Once optic zone designing is completed, the contoured lens edge is
provided by first selecting points on the surface having the optic
zone and then fitting a curve through the selected points. The x
and y coordinates are specified for the selected points on the
surface of the lens. It will be recognized by one ordinarily
skilled in the art that at least two points must be specified for
curve fitting purposes. One of the points must be located at the
optic zone periphery and one at the outermost point of the lens.
Additional points may be used and one ordinarily skilled in the art
will recognize that the more points used, the more complex the
shape of the contoured edge can be. However, lens production
machinery and process limitations may limit the number of points
that can be used.
A curve is then fitted through the selected points. The curve's
functional form may be a polynomial, a ratio of two polynomials,
trigonometric, parametric, a spline, a conic section, or a
combination thereof. The specific function and point locations used
preferably are selected so as to provide a substantially smooth
curve and the desired local thickness. The curve fitting step may
be achieved by any convenient method. For example, curve fitting
may be carried out using known numerical interpolation methods.
Alternatively, fitting may be accomplished using commercially
available software.
Referring to FIG. 1, a convex surface optic zone 11 is depicted,
which optic zone is designed in relation to base curve 12. The x
and y coordinates for points 13 through 17, shown in FIG. 2, are
selected, points 13 and 17 corresponding to the optic zone
periphery 18 and the lens' outermost point 19, respectively. A
commercially available finite element analysis software may be used
to select points 13 through 17 so that the lens thickness profile
is optimized for handling and comfort. A curve of polynomial form
is fitted through the points resulting in the substantially smooth
contoured lens edge 21 of lens 10 shown in FIG. 3.
The lenses of the invention may be formed by any convenient means.
For example, an optical cutting tool with a numerically controlled
lathe may be used to form a metallic optical tool incorporating the
contoured edge of the invention. The tool is then used to make
convex surface molds that are then used, in conjunction with
concave surface molds, to form the lens of the invention using a
suitable liquid resin placed between the molds followed by
compression and curing of the resin.
It will be understood by those of ordinary skill in the art that
various other changes of the details of the invention described may
be made. Such changes are intended to be included within the scope
of the invention claimed.
* * * * *